Floor, method for manufacturing it, and building including at least one such floor

ABSTRACT

A floor for buildings is disclosed. The floor comprises a prefabricated reinforced concrete slab (1) with a smooth flat top surface (15), said slab (1) having been cast upside-down in a mould with a smooth flat bottom (2). Said slab (1) is supported on a base (11) arranged beneath the slab (1) with the weight of the slab (1) uniformly distributed thereover. A method for making said floor is also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application is a national stage application filed under 35 U.S.C. §371 of international Application No. PCT/BE95/00024.

1. Field of the Invention

The invention relates to a floor as well as to a method for themanufacture of this floor.

2. Technological Background and State of the Art

In the field of building, the floor is a construction which constitutesa horizontal platform at the lower level of the construction work, or aseparation between two storeys.

Numerous techniques have been put forward and implemented and variousmaterials have been used to produce floors.

Featuring among the oldest known floors is, in particular, the rusticfloor formed of planks nailed to joists.

In many cases, it is preferable to produce floors from non-combustiblematerials. Particularly well known are floors consisting of reinforcedconcrete slabs poured in situ and secured to the walls or framework ofthe building. Also well known are floors formed of beams or girders(made of concrete or of metal) between which concrete blocks are placedby way of filling. Such floors composed of blocks just like those whichconsist of concrete slabs poured in situ do, however, have rather to beconsidered as constituting the fabric of floors. It is then commonplacefor such floors to be covered with a screed which is generally made witha hydraulic setting material essentially consisting of a wet mix ofcement and sand.

The production of such a floor screed leads to all the known drawbacksinherent with wet sites. The placing of hydraulic-setting materials is amessy operation during which the other bodies of craftsmen have to keepaway. Furthermore, the setting and curing of the hydraulical-settingmaterial takes a great deal of time (a few weeks), which complicates anddelays the time schedule for the work.

In any case, the production of such a floor screed requires qualifiedlabour and, despite that, the surface of the screed is never free ofdefects and its mechanical strength as well as its hydrophobia are notoptimal. In general, such a screed is further covered with a finishingcovering such as tiling, plain carpet, linoleum, etc.

According to some known techniques, a layer of thermal insulant isinterposed between the fabric of the floor and the floor screed.

It is also known for heating elements to be embedded within the floorscreed, these sometimes being electric resistors but more commonly beingserpentine coils which are connected to a feed circuit and through whicha heat-transfer fluid can be made to circulate. When heating elementsare embedded within the screed, it is obviously quite particularlyadvantageous for a thermal insulant to be interposed between this screedand the fabric of the floor.

It is also well known for an anti-vibration mat to be interposed betweenthe fabric of the floor and the screed of this floor, thus providingacoustic insulation between the storeys and reducing, in particular, thetransmission of footsteps to the storey below. Such screeds which arecommonly known as "floating screeds" or "floating slabs" may possibly beequipped with heating elements embedded within them.

Patent Application DE-A-29 30 895 describes a floor including a screedwhich rests on its support via a thermally insulating layer and anacoustically insulating layer. The screed itself is poured in situ "by awet route" and heating pipes are embedded within it.

All of these known techniques for producing floors which involve thepouring of screeds on site, inevitably lead to the drawbacks mentionedearly.

A method for producing floating screed is known according to whichsuccessive layers of plaster board are placed on a mat of anti-vibrationmaterial. When these plaster boards are laid, care is taken to staggerthe joints between the boards of one layer relative to the jointsbetween the boards of the neighbouring layers. Such a floating screed istherefore produced dry and quite cleanly but its mechanical strength andits resistance to water are insufficient for certain applications. Inany case, such a floating screed has necessarily to be covered with afinishing covering.

The anti-vibration mats used to produce floating screeds are quitefragile and therefore vulnerable. It has been possible to observe thatwith the techniques currently employed, these mats are easily damaged bythe workers producing the screed. There is therefore an excessively highrisk of the creation of "phonic bridges" which practically cancel outthe acoustic insulation properties of the floating screed.

In conclusion, it is observed that the techniques for producing floorscurrently employed have all the fairly major drawbacks regarding theproblems and constraints which they entail and/or regarding thecharacteristics of the floors produced. These problems and constraintsto which these techniques lead are felt, in particular (but notexclusively) when use is made of rapid methods of construction ofbuildings making use of prefabricated elements assembled together onsite. Using such construction methods it is highly advantageous to beable to produce the building as a "dry site". The in-situ pouring offloors or floor screeds is therefore highly ill-suited to these methods.In addition, one of the very substantial advantages of the constructionof buildings by assembling together prefabricated elements consists inthe speed of execution; a substantial part of this advantage is lost ifthe floors or floor screeds are poured in situ (and have then to set,cure and dry over a number of weeks).

OBJECTS OF THE INVENTION

Efforts have therefore been made to employ a method making it possiblerapidly to produce floors having good physical properties.

Another object of the invention is to employ such a method which makesit possible, if so desired, to produce a floor which gives good acousticinsulation between storeys.

Another object of the invention is to employ such a method which makesit possible, if so desired, to produce a floor with built-in heatexchangers.

Another object of the invention is to provide such floors having a verysatisfactory surface finish making it possible, if so desired, for themnot to be covered with an additional covering.

ESSENTIAL ELEMENTS OF THE INVENTION

The subject of the present invention is a method for producing a floorfor a building, this method including the following operations:

a) providing a mould for a reinforced concrete slab, this mouldincluding a mould bottom with a flat and smooth surface and a frameagainst which the edges of the slab will be formed, this frame beingfixed detachably to the mould bottom,

b) placing this mould in a horizontal plane, the flat and smooth surfaceof the mould bottom facing upwards,

c) placing a concrete reinforcement in this mould,

d) putting in place in this mould dismantlable securing means capable ofsecuring the bottom of the mould and the concrete slab together afterthe latter has been moulded,

e) pouring concrete into the mould and leaving the slab thus formed tocure,

f) producing a support on which the concrete slab will be placed and onwhich the weight of this slab will be distributed substantiallyuniformly, and putting this support in place in the building,

g) transporting the concrete slab contained in its mould to the saidsupport,

h) removing the frame from the mould,

i) turning the assembly formed by the mould bottom and the concrete slabupside down and placing this assembly on the said support,

j) detaching the concrete slab from the mould bottom and removing thismould bottom.

As mentioned above, it is this entire method which forms the subject ofthe invention. It will be noted that among the various operations of themethod of the invention, those indicated respectively by the letters d,f, g, i and j are particularly original.

The concrete slab used in the method according to the invention willadvantageously be produced in the factory, in a plant for castingconcrete constructional elements.

As regards the production and placement of the said support, severalalternative forms of the method according to the invention may beapplied.

According to a first one of these alternative forms, the said support isput in place in the building under construction separately and theconcrete slab (made at the factory) is transported (contained in itsmould) to the site on which the building is being constructed, where itis then put in place on its support.

According to another alternative form of the method, the said supportand the concrete slab are both made at the factory, and it is also atthe factory that the said slab is placed on its support, the assemblyconsisting of the slab and the support on which it rests then beingtransported to the construction site where this assembly is put in placein the building. This second alternative form of the method may beparticularly advantageous in the case where the support itself is aprefabricated construction element or forms part of a prefabricatedconstruction unit.

According to a preferred embodiment of the invention, the mould bottomis equipped with stiffening means mounted against its face which isopposite its said flat and smooth surface (that is to say, against itsface which, during the casting operation, faces downwards). Thisstiffening is generally necessary because the slabs to be cast whichhave a small thickness and large surface-area have to be able to betransported and handled, fixed to the mould bottom.

The mould bottom is advantageously provided with attachment meanscapable of making it easier for it to be handled by cranes or otherlifting means.

According to a preferred embodiment of the invention, an anti-vibrationmat is interposed between the concrete slab and its support. Afloating-slab floor is thus obtained.

The floor slabs produced according to the invention are slabs which arethin but generally have a large surface-area.

In most cases, the floor of a room of the building may be produced witha single prefabricated slab according to the invention. For large sizedrooms in the building, it may be necessary or advantageous to producethe floor by the juxtaposition of two or more slabs according to theinvention. This is because it is important that the size of these slabsshould not prevent their handling and their transportation.

The upper surface of the slabs put in place is, in any case, perfectlyflat and smooth which means that for many applications it is unnecessaryto cover them with a covering.

The appearance of the upper face of the floor slab may be furtherimproved by employing a specific embodiment of the invention, accordingto which, before the concrete is poured into the mould, a layer ofmortar supplemented with filler materials or with pigments capable ofgiving the upper face of the slab a decorative appearance is first ofall poured into this mould.

When casting the concrete slab it is advantageous to vibrate theconcrete as is commonly done.

According to a particular embodiment of the method according to theinvention, a serpentine coil capable of conveying a heat-transfer fluidis arranged in the mould prior to the pouring of the concrete. Thisserpentine coil is arranged such that its ends exit via a lateral edgeof the slab.

According to an advantageous embodiment of the method according to theinvention, the mould is of a shape such that a rebate is formed alongthe edge of the face of the concrete slab which is in contact with thebottom of the mould.

Another subject of the invention is a floor for a building including acontinuous, coherent and cured layer of hydraulic setting material and asupport situated beneath the said layer and over which the weight ofthis layer is distributed substantially uniformly. In the flooraccording to the invention, the said layer consists of a prefabricatedslab of reinforced concrete, the upper face of which has a flat andsmooth surface, this slab having been cast upside down in a mould thebottom of which has a flat and smooth surface.

According to a preferred embodiment of the invention, the floor includesan intermediate layer between the said support and the concrete slab.

This intermediate layer may possibly be thin (a few millimeters) andconsist, for example, of a rot-proof felt capable of compensating forsmall unevennesses exhibited by the upper face of the support and thelower face of the slab, so as to distribute the weight of the slab asuniformly as possible over the support.

The intermediate layer will advantageously consist of an anti-vibrationmat so that the concrete slab is a floating slab thus giving goodacoustic insulation between storeys and, in particular, damping out thetransmission of footsteps towards the storey below.

The intermediate layer may just as easily be made of a thermalinsulation material.

When an anti-vibration mat is interposed between the support and theconcrete slab, this anti-vibration mat already provides quite goodthermal insulation but it may be desirable to interpose a layer made ofa material providing good thermal insulation between the anti-vibrationmat and the concrete slab.

The thermal insulation of the concrete slab relative to its support isobviously particularly important when heating elements (or, moregenerally, heat exchangers) are embedded within the concrete slab.

The concrete slabs used for producing the floors according to theinvention are, as a general rule, thin and of a large surface-area.

According to an advantageous embodiment, the concrete slabs used have asurface-area of at least 3 m² and preferably at least 6 m². Thethickness of these slabs is advantageously between 3 and 7 cm, and, forpreference, between 4 and 6 cm.

In order to produce the floors according to the invention, use may bemade of very diverse supports.

The support for the prefabricated concrete slab according to theinvention may especially consist of a continuous slab of concrete pouredin situ (but the upper surface of which is therefore not perfectly flatand smooth).

The support for the concrete slab according to the invention may just aseasily consist of a series of beams or girders (made of metal or ofconcrete). Since it is desirable for the concrete slabs to be thin, theseparation between the supporting beams or girders has therefore to takethis into account. In most cases, this separation will be less than 40cm.

According to a specific embodiment of the invention, the supportconsists of a profiled sheet such as a trapezoidal sheet.

The concrete slab of the floor according to the invention may include,embedded within it, at least one serpentine coil capable of conveying aheat-transfer fluid and connection means for connecting this serpentinecoil to a feed circuit.

According to a specific embodiment, the concrete slab has a shape whichis basically rectangular with chopped corners. When such a slab isprovided with a serpentine coil, the means for connecting thisserpentine coil are advantageously situated in the chopped-off cornersof the slab.

According to a specific embodiment, the concrete slab includes a rebatealong the edges of its upper face, this rebate being capable ofinteracting with a joint laid between two neighbouring slabs.

When two neighbouring slabs are provided with such a rebate, a profiledjoint with a T-shaped cross-section is preferably inserted between them,the dimensions of each rebate corresponding to those of one of thebranches of the T-section.

The subject of the invention is also a building which includes at leastone floor in accordance with the invention or produced according to themethod in accordance with the invention.

One of the important advantages of the technique according to theinvention consists in the fact that it allows the very rapid and dryproduction of floors having good properties. The concrete slabs may becast at the factory, away from the work site, several weeks before theslabs have to be put in place in the building under construction.

This method of producing floors may be used for buildings of verydiverse types.

The economical advantage of the method is of particular importance whenquite a large number of slabs have to be produced for a site or for aseries of sites.

It will be understood that it is advantageous to be able, as far aspossible, to produce slabs in a small number of formats.

It is especially for this reason that the advantages of the methodaccording to the invention are particularly substantial when this methodis applied to the production of floors in modular buildings andespecially in buildings produced by assembling together prefabricatedconstruction units of standardized dimensions.

BRIEF DESCRIPTION OF THE DRAWINGS

Other specific features and advantages of the invention will emerge fromthe description below of one particular embodiment of the invention,this being applied here more specifically to buildings produced by theassembling together of modular construction units, reference being madeto the attached drawings, in which:

FIG. 1 is a perspective view of a slab according to the invention,during the manufacturing stage;

FIG. 2 is a view in section on a vertical plane II--II of a detail ofthe slab of FIG. 1;

FIG. 3 is a perspective view of a slab after it has been put in place onthe lower horizontal element of a modular construction unit;

FIG. 4 is a view in section on the vertical plane IV--IV of FIG. 3;

FIG. 5 is a perspective view of a slab including heating elementsembedded within it;

FIG. 6 is a perspective view, with cutaway, of a slab with heatingelements, placed on the lower horizontal element of a modularconstruction unit.

FIG. 7 is a prespective view of a frame which surrounds the edges of theslab shown in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

The floating slab according to the invention, by contrast with aconventional "floating screed" is not produced in situ but in a mould,to the desired dimensions.

The slab 1, made of reinforced concrete, is represented in FIG. 1resting on the bottom 2 of the mould in which it was made. The otherparts of the mold, which are intended to form edges 3 of the slab 1, donot have any specific features, but may comprise a frame 3a, which isshown in FIG. 7 The edges 3 of slab 1 are formed against the frame 3a,which is fixed detachbly to bottom 2 of the mold.

The slab 1 is secured to the mould bottom 2 by dismantlable fixtures 4which can be seen in greater detail in FIG. 2.

By virtue of these fixtures 4, it is possible to manipulate and turnover the slab 1 with its mould bottom 2 quite simply without the risk ofbreaking or cracking this thin slab (thickness 5 cm).

FIG. 2 shows on a larger scale the slab 1 in section at the point of oneof these dismantlable fixtures 4.

The fixture 4 represented essentially includes a tubular element 5intended to be embedded within the slab 1. This tubular element 5 isinternally threaded and interacts with a bolt 6 which holds it in placerelative to the mould bottom 2. Fixed to the end of this tubular element5 is a flange 7 intended to distribute the stresses exerted on thefixture 4 through the slab 1 after the concrete of which it is composedhas set. FIG. 2 represents, in section, elements of a lightweightreinforcement 8 embedded within the slab 1.

The flange 7 is represented in FIGS. 1 and 2 lying flush with thesurface 9 of the slab; this does not in any way detract from theappearance of the slab 1, as this surface 9 is intended to form thelower face of the slab 1 once the latter has been turned over and put inplace.

In order to detach the slab 1 from the bottom of the mould 2 after thecured slab 1 has been put in place, all that is required is to unscrewthe bolt 6, the head of which is accessible. It will be obvious to thoseskilled in the art that it is possible to use a number of alternativeforms of this fixture 4 for the same function without departing from thescope of the invention.

The mould bottom 2 also includes stiffeners 10. The presence of thesestiffeners 10 may be explained by the small thickness of the slab 1 andby its large dimensions, which correspond substantially to those of thelower horizontal element 11 of a prefabricated construction unit 12, asmade be seen in FIG. 3. The lower horizontal element 11, which isdescribed in greater detail below, acts as a support for the slab 1. Thecorners 13 of the slab 1 are chopped off so as to match the specificshape of this modular construction unit 12, which consists essentiallyof a lower horizontal element 11 in the form of a box and of posts 14with a V-shaped section which can be erected at each corner of thislower element 11.

The V-shaped form of these posts 14 allows the electrical circuits andpipework serving the storeys below or above of the building (notrepresented) in which the construction unit 12 is intended to beincorporated to be routed down their channel.

The chopped-off corners 13 of the slab 1 give easy access allowing therouting of these circuits and pipework, as explained later.

That face of the mould bottom 2 which faces the slab 1 has a goodsurface finish, and this straight away gives the corresponding face 15of the slab 1 a smooth and cared-for appearance. It is this actual face15 with caredfor appearance which is used as the upper face of thefloating slab 1, after turning upside down and mould release.

As there is therefore no limitation imposed by the characteristics of amixture which lends itself to smoothing (fluidity, setting time, etc),it is possible, in order to produce the slab 1 according to theinvention, to use any type of concrete making it possible to obtain areinforced concrete slab 1 which has the desired mechanical or physicalproperties (hydrophobia etc).

The slab 1 according to the invention, intended to be put in place as afloating slab, can be manufactured at the factory. Thanks to thisfactory prefabrication, the organization and programme of constructionof a building are therefore not impeded or slowed down by the settingand drying-out time of the floating slab.

It will be understood that in these conditions, it is possible to lay ananti-vibration mat 16 with greater care and with less danger of damagingit than on a conventional work site.

It is even possible to effect a quality control directly after laying,with almost instantaneous location of any (improbable) defect and toremedy such a defect immediately.

The slab 1 represented in FIG. 3 was poured with standard dimensionscorresponding to those of the lower horizontal element 11 of aconstruction unit 12, which may represent twenty square meters or so.For reasons of ease of handling, it may be possible to produce such afloating slab 1 from several smaller and therefore more handlable parts17 (of +6 m² for example).

These parts 17 (bounded by broken lines in FIG. 3) are assembledtogether by conventional methods for the assembly of sheets ofreinforced concrete, once put in place on the lower horizontal element11 of the modular construction unit 12.

FIG. 4 shows, in greater detail, a connection between two floating slabs1 according to the invention, each one laid on the lower horizontalelement 11 of juxtaposed construction units 12, as represented in FIG.3.

As these floating slabs 1 have a smooth and beautifully finishedappearance, they make the presence of an additional decorative coveringsuperfluous. The absence of such a covering does, however, make itnecessary for the joints between two neighbouring slabs 1 to have aparticularly clean appearance.

To this end, a rebate 18 is formed during casting along the perimeter ofthe upper face 15 of each floating slab 1.

A joint 19 which is in the form of a T-shaped extruded section isinserted at the joint between two floating slabs 1.

The thickness of the bar of the T corresponds to the depth of therebates 18 so that the top of the joint 19 comes just level with theupper surface of the two floating slabs 1, avoiding any visiblediscontinuity.

The joint 19 is preferably made of an elastic material with a lowthermal conductivity (such as a plastic) so as to avoid the creation ofan acoustic bridge between two neighbouring slabs 1.

The laying of such a joint 19 implies that the rebates 18 have to havevery tightly controlled dimensions, something which cannot be obtainedwith a conventional floating screed, but is easily achieved by virtue ofthe method of casting adopted for this slab 1.

FIG. 5 shows an advantageous embodiment of a floating slab 1 accordingto the invention, which comprises heating elements 20 embedded withinthe slab 1.

Floor heating is known to cause few problems provided it has been laidproperly. In the case of this floating slab 1, the heating engineers canwork under optimum conditions, because they can get on with laying theheating elements 20 in a specially fitted-out factory, namely away fromall the constraints of time scales and of inclement weather imposed bywork on site.

If required, it may even be possible to envisage the laying of severalheating elements 20 with different powers, the only technicalrestriction being that of being able to connect the heating elements 20after the slab 1 has been put in place.

When laying the heating elements 20 it is advantageous for theconnecting means (connections, etc) for these heating elements 20 to bearranged in the chopped-off corners 13 of the floating slab 1, so thatthey can easily be connected to the circuits laid in the channels of theposts 14.

FIG. 6 shows, in perspective, a section with cut-away of a floating slab1 put in place on the lower horizontal element 11 of a construction unit12.

In particular, it is possible to see in this section the remaining parts5, 7 of the fixtures 4 which were used, before it was put in place, tohold the slab 1 on the mould bottom 2.

Now that the mould bottom 2 has been removed, small orifices remain onthe upper face of the slab 1, and these, once plugged, become almostinvisible.

The cut-away makes it possible also to see the reinforcing elements 8embedded in the slab 1.

The upper face 15 of the slab 1 has all the qualities of a finishedcovering (hardness, resistance to water and to moisture). In order toimprove its aesthetic qualities it is possible, when casting, to spreadand distribute over the mould bottom 2 a layer of a mixture of mortarsupplemented with a filler (dyes, decorative granules, etc) giving thesurface 15 of the demoulded slab 1 a decorative appearance, of thegranite-like type for example, which makes additional coveringsuperfluous.

I claim:
 1. Method for producing a floor for a building, including thefollowing operations:a) providing a mould for a reinforced concreteslab, this mould including a mould bottom with a flat and smooth surfaceand a frame against which the edges of the slab will be formed, thisframe being fixed detachably to the mould bottom, b) placing this mouldin a horizontal plane, the flat and smooth surface of the mould bottomfacing upwards, c) placing a concrete reinforcement in this mould, d)putting in place in this mould dismantlable securing means capable ofsecuring the bottom of the mould and the concrete slab together afterthe latter has been moulded, e) pouring concrete into the mould andleaving the slab thus formed to cure, f) producing a support on whichthe concrete slab will be placed and on which the weight of this slabwill be distributed substantially uniformly, g) transporting theconcrete slab contained in its mould to the said support, h) removingthe frame from the mould, i) turning the assembly formed by the mouldbottom and the concrete slab upside down and placing this assembly onthe said support, j) detaching the concrete slab from the mould bottomand removing this mould bottom.
 2. Method according to claim 1, whereinthe support is put in place in the building under constructionseparately and the concrete slab made at the factory, is transported,contained in its mould, to the site on which the building is beingconstructed, where the slab is then put in place on the support. 3.Method according to claim 1, wherein the support and the concrete slabare both made at the factory, and it is also at the factory that theslab is placed on its support, the assembly consisting of the slab andthe support on which it rests then being transported to the constructionsite where this assembly is put in place in the building.
 4. Methodaccording to claim 1, wherein the mould bottom is equipped withstiffening means mounted against its face which is opposite its saidflat and smooth surface.
 5. Method according to claim 1, wherein themould bottom is provided with attachment means capable of making iteasier for it to be handled by cranes or other lifting means.
 6. Methodaccording to claim 1, further including the following operation, priorto putting the concrete slab in place on its support.placing ananti-vibration mat on the upper face of the said support.
 7. Methodaccording to claim 1, further including before pouring the concrete intothe mould, the following operation:pouring into the bottom of the moulda layer of mortar supplemented with filler materials capable of givingthe upper face of the slab a decorative appearance.
 8. Method accordingto claim 1, wherein the concrete of the slab is vibrated.
 9. Methodaccording to claim 1, further including the following operation:placingin the mould, prior to the pouring of the concrete, at least oneserpentine coil capable of conveying a heat-transfer fluid, the ends ofthis serpentine coil exiting via a lateral edge of the slab.
 10. Methodaccording to claim 1, wherein the said mould is of a shape such that arebate is formed along the edges of the face of the concrete slab incontact with the bottom of the mould.